Endodontic therapy or root canal therapy is a sequence of treatment for the infected pulp of a tooth which results in the elimination of infection and the protection of the decontaminated tooth from future microbial invasion. Root canals, and their associated pulp chamber, are the physical hollows within a tooth that are naturally inhabited by nerve tissue, blood vessels and other cellular entities. Together, these items constitute the dental pulp. Endodontic therapy involves the removal of these structures, the subsequent shaping, cleaning, and decontamination of the hollows with small files and irrigating solutions, and the obturation (filling) of the decontaminated canals.
The success rate of conventional endodontic therapy is 85-95%. If conventional endodontic treatment is unsuccessful, non-surgical root canal retreatment will eliminate the problem. If retreatment of root canal is not possible because of natural, restorative or iatrogenic obstructions, endodontic surgery is indicated. Root-end surgery includes surgical debridement of pathological peri-radicular tissue, root-end resection, root-end cavity preparation and filling of the root-end cavity to seal the root canal effectively.
Traditionally, the root-end cavity is prepared with burs used with low-speed handpiece. Cavity preparation with burs has some disadvantages including limited operative field and root-end bevel, which increases the number of exposed dentinal tubules on the root-end surface. Ultrasonic surgical tips have been introduced as an alternative to the burs for root-end cavity preparation, and was able to solve some of these problems. Ultrasonic root-end preparation allows cleaner and deeper cavity centered in the root canal and reduced bevel angle.
There are several ultrasonic surgical tips with different shapes and sizes. Early tips were made of stainless steel, and some have special surface coatings to increase their cutting efficiency. Diamond-coated ultrasonic tips are very efficient for removing gutta-percha from the root-end cavity. Also, zirconium-nitride-coated tips are very efficient and provide good vision. Examples of such ultrasonic tips include KiS tips from Kerr Dental of Orange, Calif., and ProUltra ENDO ultrasonic instruments from Dentsply Sirona of York, Pa.
Despite advances in the field, there remains a need for an ultrasonic root end retro-preparation endodontic apical surgical instrument which is easier to use and more effective.